The New York Trilogy [suggested by Ross Allatt]

The New York Trilogy is perhaps the most astonishing work by one of America’s most consistently astonishing writers. The Trilogy is three cleverly interconnected novels that exploit the elements of standard detective fiction and achieve a new genre that is all the more gripping for its starkness. It is a riveting work of detective fiction worthy of Raymond Chandler, and at the same time a profound and unsettling existentialist enquiry in the tradition of Kafka or Borges. In each story the search for clues leads to remarkable coincidences in the universe as the simple act of trailing a man ultimately becomes a startling investigation of what it means to be human. The New York Trilogy is the modern novel at its finest: a truly bold and arresting work of fiction with something to transfix and astound every reader. [product description from Amazon]
The novel has a Wikipedia page.
Author’s Wikipedia page.
Author’s website.
Shortlisted for this month
This month’s selection used “the alternative” strategy — everyone brought a suggestion. This time round only one was disqualified. The two other books receiving most votes were:
The Dice Man [suggested by Phil Howarth]

The rules are down to you. The rules that stop you seducing your neighbour downstairs, that stop you hitting your boss, that stop you leaving your family and leaving the country. The rules that stop you living.
The dice don’t do rules; the dice do life.
Luke Rhinehart is a psychiatrist, a husband and a father, his life locked down by routine and order — until he picks up the dice. The dice govern his every decision and each throw takes him further into a world of risk, discovery and freedom. As the cult of the dice grows around him the old order fades: chance becomes his religion, the dice his god.
If you haven’t lived the life of the dice, you haven’t lived at all. Let the dice decide. And roll with it. [product description from Amazon]
The novel has its own Wikipedia page.
Author’s Wikipedia page (in his pen name, and the name of the narrator of the book, rather than his birth name – George Cockcroft).
The Day of the Triffids [suggested by Wendy Gibson]

When a freak cosmic event renders most of the Earth’s population blind, Bill Masen is one of the lucky few to retain his sight. The London he walks is crammed with groups of men and women needing help, some ready to prey on those who can still see. But another menace stalks blind and sighted alike. With nobody to stop their spread the Triffids, mobile plants with lethal stingers and carnivorous appetites, seem set to take control.
The Day of the Triffids is perhaps the most famous catastrophe novel of the twentieth century and its startling imagery of desolate streets and lurching, lethal plant life retains its power to haunt today. [Product description from Amazon]
The book has a Wikipedia page and was made into a film in the early 60s, which also has its own Wikipedia page. In 2009 there was also a single-season TV series.
Author’s Wikipedia page.